With the current trends in the avionics business toward improving ergonomics and image quality of displays, it is becoming increasingly important to provide a liquid crystal display with a uniform brightness across the display panel.
Basically, backlighted liquid crystal displays utilize a backlight to generate a white light which is filtered by a liquid crystal filter to create an image. The backlight is frequently an incandescent or fluorescent lamp which typically is placed between a diffuser and a back reflector. The area on the diffuser centered in front of the lamp is typically brighter than the area of the diffuser around its edges. The bright spots have been attenuated in the past, by methods such as placing light absorbing dots on the lamp side of the diffuser adjacent the lamps.
While this design, or variations of it, have enjoyed significant use in the past, it does have several serious drawbacks. A major drawback with the light absorptive dots placed on the lamp side of the diffuser is that it causes an overall reduction in the brightness of the liquid crystal display panel. Another problem with such a design is that the absorptive dots typically absorb heat as well as light and thereby create a panel with a higher overall operating temperature.
Consequently, there exists a need for an improvement and advancements in the design of liquid crystal display panels which provide for a more uniform brightness across the liquid crystal panel with concomitant increase in overall panel brightness without any increase in the lamp power or operating temperature.